Trench digging machines



Dec. 11, 1962 J. A. HOWARD TRENCH DIGGING MACHINES 2 Shets-Sheet 1 Filed April 25, 1960 FIGI.

FIGS.

INVENT R n R I w T H r h Mr T P\ N kn D J DC. 11, 1962 J A H RD TRENCH DIGGING MACHINES 2 Sheets-Sheet 2 Filed April 25, 1960 IIVVE m'ore J M IfRTH IP L Wfi D Q! D'y 7 1M ATM United States atent O 3,067,533 TRENCH DIGGING MACHINES John Arthur Howard, West Horndon, England, assignor to Rotary Hoes Limited, West Horndon, England Filed Apr. 25, 1960, Ser. No. 24,412 Claims priority, application Great Britain Apr. 28, 1959 1 Claim. (Cl. 3794) The invention relates to a trench digging machine of the kind having a drivable digging wheel, supported on a transverse horizontal axis, provided peripherally with digging tools which each comprise a flat root portion secured to the wheel with its plane parallel to the plane of rotation of the latter, and a laterally-extending, flat, operative portion, and the object of the invention is to divert to one side of the machine such of the soil, lifted by the digging wheel during the digging operation, as is entrained by the radially-inner surfaces of the operative portions of the tool and the digging wheel. The word entrained is used herein to cover the case where the earth actually adheres to the parts in question and the case where the earth is carried round without adhering to them.

According to the invention a trench digging machine, of the kind set forth, includes a drivable rotary member, supported so as not to rotate bodily with the digging wheel, having its rotational axis normal to a plane containing the axis of the digging wheel and arranged, at the side of the digging wheel towards which the operative portions of the tools extend, to work close up to the adjacent side of the digging wheel, and to the radially-inner sides of the said operative portions of the digging tools without being in their path so as, during the respective rotations-of the digging wheel and rotary member, to divert to one sideo'f the machine the earth entrained by the said radially inner sides of the said operative portions and the digging wheel during the digging of a trench.

The rotary member can have a peripheral arrangement of fingers for removing the raised earth, and it can, according to a further feature, be associated with a deflector plate which is arcuate about the tips of the fingers and serves to divert the removed earth to one side of the machine.

Preferably the drives for the digging wheel and rotary member are derived from a common source such, for instance, as from a power take-off shaft of a tractor to which the machine is attached, or from a driven shaft of the digging machine if the latter is adapted to be self-propelled, but as the rotary member is clear of the digging tools any need for driving the digging wheel and rotary member in timed relationship is avoided.

A stationary scraper may be provided for scraping adhered earth from the digging wheel.

In the accompanying drawings:

FIGURE 1 is a diagrammatic rear perspective view of a trench digging machine of the kind set forth attached to the rear of a tractor having a power take-off shaft to provide the power for operating the machine, which latter is shown in a raised position;

FIGURE 2 is a side elevation, looking in the direction of the arrow 2 in FIGURE 1, of an upper portion of the digging wheel and one form of means in accordance with the invention, drawn to a larger scale, the figure also showing a deflector plate and a stationary scraper not shown in FIGURE 1;

FIGURE 3 is a section on the line 33 of FIGURE 2 and drawn to the same scale;

FIGURE 4 is a detail view in the direction of the arrow 4 in FIGURE 3;

FIGURE 5 is an enlarged view of the deflector plate and stationary scraper, shown in FIGURE 3; and

FIGURE 6 is a view in the direction of the arrow 6 in FIGURE 4 but drawn to a smaller scale.

Referring first to FIGURE 1, the machine includes a digging wheel 10 which is supported at its remote side fro-m a frame 11 which can be moved along vertical guides 12 by a hydraulic piston and cylinder arrangement 13 so that the machine can be raised or lowered for varying the depth of the trench to be dug. The machine includes a transverse shaft in a tubular casing 14 adjacent the top of the digging wheel, and this shaft is driven through a suitable transmission 15, 16 from the tractor power take-off shaft and drives a pinion meshing with an internally-toothed wheel fast within the periphery of the digging wheel at the far side in FIGURE 1.

The digging wheel has a radially-directed peripheral flange 17 to which the longer legs 18 of a circumferential arrangement of substantially L-shaped tools are flatly secured, and the other legs 19 of these tools extend laterally at an appropriate rake angle for cutting and lifting the earth for the digging of the trench. practice, particularly when digging moist ground, that the earth being dug adheres to, or is carried round by the tools and digging wheel, the earth being particularly prone to adhere to those sides of the tool legs 19 which are nearer the axis of the wheel, and in the angles between the legs 19 and the adjacent face of the wheel.

The structure as thus far described does not form part of the invention, and-has been included only for the purpose of assisting in a comprehension thereof.

A bracket 20 fast with the frame 11 supports an upright tube 21 within which is a shaft 22 connected to be driven at the top by angle gearing within a casing 23, fast with the tube 21, from a universally-jointed telescopicallyextensible shaft 24. The latter is driven from the transverse shaft in tubularcasing 14 by worm gearing within a casing 25 mounted on the casing 14.

Adjacent the lower end of the vertical shaft 22 is a coaxial disc 26 having, on its upper surface four outwardly-extending fingers of which the outer ends, when the disc is rotated, have a path bringing them closely adjacent the radially-inner sides of the legs 19 of the digging tools and close to the adjacent side surface of the digging wheel 10. Each of these fingers, as shown in FIGURE 3, has a straight portion 27 contiguous with a forwardlybent, straight operative portion 28 and each comprises a main strip of metal formed as aforesaid and backed by a reinforcing strip 29 of which the outer end is curved to support the inner end of the forwardly-bent operative portion but does not extend to the outer end of the latter.

For supporting each of the fingers 27, 28 the upper face of the disc 26 is provided with four equi-circumferentially-spaced, rectangular mounting blocks 30 which are welded in position with their major dimensions directed along a chord of the disc so that the major dimension of each block is at right-angles to those of the blocks which cyclically precede and succeed it.

Each finger has its inner end secured by a bolt 31 to the associated block 30, and it extends outwardly through a bridge-like member 32 welded to the disc and the mounting block 30 for the adjacent finger. The members 32 provide clearance for resilient bending of the fingers about their anchored inner ends, but serve as stops to limit that bending to a safe value.

It will be seen from FIGURE 2 that the disc 26 is held up to a shoulder on shaft 22 by a spring 34 held in position by a nut 35 and locknut 36 engaged on a screwthreaded lower extension of the shaft. This allows the disc to be displaced resiliently in the downward direction if the fingers 28 encounter large clods adhered under the tools 18, 19. Also from the same figure it will be seen that the leading edge of each tool leg 19 is provided with a somewhat outwardly-directed wear resistant tip 19a Itis found in 3 which,..as shown in FIGURE 3, is of greater width than the limb 19. FIGURE 3 also shows at 37 screws for holding the'tool legs 18' flatly against the wheel flange 17.

In operation the digging wheel is rotated in the direction indicated by the arrow 38in FIGURE 3, and the disc 26 in the direction indicated by the arrow 39. The adjacent portions of their peripheries therefore move in the same direction, but it is arranged for the peripheral speed of the tips-of the fingers 28, which sweep the circletit-to be greater than that of the'flange 17' so that the tips of the fingers will overtake the tools 18, 19. In doing this the fingers 28 sweep closelyinto the angle between the tool legs 19 and the face of the flange 17 so as to dislodge earth adhering in the angles. This dislodged earth is carried by the fingers 28 up to a deflector plate 41 which'is of greater height than the said fingers and diverts the earth to one side of'the machine. The deflector plate is-welded at 42 to a plate 43' which is supported fromparts 44 and45 (see FIGURE 1') of the machine frame by bolts 46.

Preferably the plate 43 supports a stationary scraper for removing earth from the flange 17. This scraper is carried bya plate 47 which lies flatly on plate 43 and is heldin an adjusted position by screws 48 extending through slots 49. The scraper comprises a stationary plate'50fast with the plate 47 and strutted' at 51, and

it'acts asa support-for a holder 52 for a'scraping tool 53. Screws 54 in the plate 50 engage slots 55 in'the tool holder, and the latter similarly-supports the tool by screws 56 and slots 57. Preferably the tool has a renewable scraper member 58;

What I claim as my invention and-desire to secure by Letters Patent ofthe United States is:

A trench digging machine comprising a frame, a digging wheel journalled on a transverse horizontal axis in said fram a plurality'of digging tools each'having a flatroot portionand'a' laterally-extending flat operative portion,

saiddigging tools secured by their root portions to said" digging wheel-in circumferentially-spacedpositions with portions extending at one side of said digging Wheel, a

rotary member at the side of said digging wheel to which the operative portions of said digging tools extend, said rotary member supported from said frame with its rotational axis normal to a plane containing the axis of the digging wheel, said rotary member provided peripherally with outwardly extending fingers having-tips, a deflector plate over which said tips move supported from said frame, said deflector plate having an upstanding wall arcuate about said tips of said fingers, and means adapted to drive said digging wheel and rotary member, said rotary member arranged for tips of said fingers to work clear of but close up to said digging wheel and to those sides of the operative portions" of said digging tools which are presented towards the axis of said digging wheel so as, during the respective rotations of the digging wheel and rotary member, to divert to one side of the machine the earth entrained by the digging wheel and said sides of said operative portionsof said tools during the digging of a trench, a scraper element adjacent the entrance end ofsaid deflector plate, a mounting plate for said scraper element, means to adjustably position the mounting plate on said deflector plate, and said deflector arranged to divert the earth from saidfinger's'to the side of said machine from'which said operative portions of said digging tools extend References Qitedin the file of this patent UNITED STATES PATENTS 219,515 Plumb Sept; 9, 1879 2,877,576 Radestock Mar. 17, 1959 2,892,271 Frick June 30, 1959 2,979,837 Hunter Apr. 19, 1961 FOREIGN PATENTS 571, 14 Great Britain Sept. 14 1945 597,344 Great Britain Jan. 23', 1948 

